Switching arrangement for motor vehicle change speed gears



July 23, 1957 A. ZITTRELL I 2,800,033

f SWITCHING ARRANGEMENT FOR MOTOR VEHICLE CHANGE SPEED GEARS Filed May 27, 1954 2 Sheets-Sheet l A. ZITTRELL July 23, 1957 SWITCHING ARRANGEMENT FOR MOTOR VEHICLE CHANGE SPEED GEARS Filed May 27, 1954 2 sheets-sheet 2 SWIICHING ARRANGENIENT FOR MTR VEHICLE CHANGE SPEED SEARS Anton Zittrell, Friedrichshafen am Bodensee, Germany,

assigner to Zaiinradfabrilt Friedrichshafen, Friedrichshaten am Bodensee, Germany Application May 27, 1954, Serial No. 432,53

Claims priority, application Germany .inne 12, 1953 Z Ciairns. (Cl. 74-473) The present invention relates to a switching arrangement for motor vehicle change speed gears with several switching rods which are arranged adjacently and are slidable longitudinally and provided with cut-out portions and a switching member which engages into the cut-out portions in order to allow the displacement of one of the switching rods.

There are known already switching arrangements which have several parallel switching rods which can be actuated by means of a drive switch lever provided with a finger and with the cooperation of locking bodies and locking plates. This known type of switching arrangements consists of many single parts which move in their bearings with a play and cause a large total play of the switching arrangement.

The switching arrangement of the present invention does not have any special locking bodies and avoids therefore the above mentioned disadvantage. The switching rods are displaced in the present invention by means of a switching member which is mounted rotatably and displaceably transversely to the switching rod shaft which switching member has several switching cams which reach into cut-out portions of the switching rods, the cams lying in several planes which are perpendicular to the switch sleeve axis switching cams and/r the cut-out portions in the switching rods are arranged in respect to the axis characterizing the neutral position of the switching cam unsymmetrically in such a way that each switching cam begins its action from its neutral position only in one rotational direction of the switching member.

A preferred embodiment of the invention provides a switching cam which is executed as an unsymmetrical member of uniform thickness, that is, a switching cam the front and back edges of which have a circular form and have the same center of curvature, the front edge having a larger radius of curvature than the back edge. The cut-out portions in the switching rods are rectangular. With such a form of cam and of the cut-out portion it is achieved that at the beginning of the switching movement from the neutral position of the cam the greatest effective switching force can be exerted.

In the known switching levers the effective lever arm length is a multiple of the width of the switching finger. This type of construction makes necessary a high drive housing. Furthermore the effective lever arm length along the switching lever movement is approximately constant.

A characteristic sign of a switching arrangement of the present invention is the short compact form of the switching cam. rhe effective switching force at the beginning of the stroke of an unsymmetrical switching cam can be approximately twice as large as the effective switching force at the end of the stroke.

A preferred form of a switching arrangement according to the present invention consists of a switching member in the form of a spline shaft with several switching cams which are made uniform throughout and in the shape of a dise. and with a bore which is appropriately ICC grooved with respect to the spline shaft. The cam discs are usually attached on the spline shaft by placing sepa rating rings intermediate thereto and arranged in rows on the spline shaft like a mirror image.

The front edge of the switching cams and thus the cut-out portions of the switching rods are displaced in such a way with respect to an axis which is perpendicular to the switching rods that the working edges of the cut-out portions can be worked on with a gang cutter in the same clamping operation.

The switching sleeve can be displaced by a known lever which is ball mounted. There can be provided, however, especially in connection with a switching rod arrangement which is fastened to a steering wheel also a switching lever which is displaceable longitudinally in a known manner and which is rotatable, which switching lever actuates an angle arm fastened to the switching sleeve shaft.

The switching cam can also be provided with a front and back edge which is bent in an involute manner and the switching rod be made with a cut-out portion in the shape of a trapezoid.

Furthermore one can use a cam provided with a front and back edge of the same curvature in connection with a cut-out portion the front and back edges of which lie at a right angle to the switching rod shaft and are of unequal lengths.

In the attached drawing several embodiments of the invention are shown and they indicate:

Figure l a front view of the switching iever and of a switching rod with a drive housing in section,

Figure 2 a plan view of the three switching rods with the switching cams, the latter in a section along line A-B (Fig. l).

Figure 3 shows a plan view of the three switching rods with the cut-out portions and their treatment by means of gang cutters.

Figure 4 a side view of the switching sleeve with the three switching rods, an actuating lever and drive housing in cross section.

Figure 5 shows a further embodiment of a switching lever.

Figure 6 shows a switching cam according to Figure l in an enlarged scale.

Figure 7 shows a further embodiment of a switching cam with an unsymmetrical form of the cut-out portion.

In Figure l is indicated by 1 a switching sleeve, which is rotatable on a shaft 2 in the mounting eyes 3 and 4 (see Figure 4) and mounted displaceably in the direction of the shaft. The switching sleeve 1 is provided with switching cams 5, 6, 7 which are distributed at certain intervals along the switching lever axis and displaced radially with respect to each other. The switching cams 5, 6, 7 can be brought into engagement with cut-out portions 3, 9, 10, 11, 12 by rotation and displacement of switching sleeve 1, which cut-out portions are provided on the three switching rods 13, 14, 15 which are arranged parallel next to each other and displaceable along their axis (see Fig. 2).

The switching rod 13 has two, the switching rods 14 and 15 each three notches, 16, 17, 1S, which lie adjacently into which a spring biased ball 19 sets (Fig. l). The switching cams 5, 6, 7 have a front Vedge 20 which is preferably rounded oit in a circular shape and a similarly rounded oif back edge 21 with substantially smaller rounding oi radius and the central switching cam 6 lies like a mirror image with respect to the switching cams 5 and 7. The switching movement of the switching rods 13, 14, 15 from the neutral position shown into the intended gear position is started each time through front edge 20 of one of the switching cams 13, 14, 15. The returning of the switching rods into their neutral position obtained by the back edge 21 of the switching cams. The larger rounding off radius of the front edge 20 of the switching cams acts `in such a way that at the beginning; ci the switching movement .from-the :neutral positionfor thea-switching-rods there is, :with` the. switchingrno'mentA remainingequal, exerted a larger vforce on the switching members than there Yis toward the. end o the-switching movement. The'property of the switching cam .of thefpresent invention .works out .favorably with switching vdevices having locking synchronization which require at .the beginning of `the .coupling movement a larger switching force. l v Y In Figure 2 the switching-rods 13, 14., 1S and the drive housing-.29: are shown` in plan view. The switching sleeve 1j withY atplateSZisshown iii-.phantom lines. The switching rods .are lmountedr .non-rotatably and .longitudinally slidabieinzthe bearing .ledges-22 .and 23. Qnv the. side directed toward theswitohingsleeve 1 (Fig. 1) the switching mdszare 4provided with ledges 35, vwhich have cut-.out

' portions $3.519, 1.0, -111 and 12, into which reach the switching cams .5, 6;, .7' .of yswitching sleeve 11. Switching rod 13 for the reverse gear has the cnt-outrportion 8.A Switchingrod 14 has:.a-cutout-portion 9'for the third gear and a cut-out portion for the. second gear. Switching rodV 15 has cut-.out portions. 11 for the fourth gear and I2 Yfor .the .first gear. The corresponding gears and drectionsoengagementare indicated by arrows, the letter R and the numerals 1 to 4. The ledges 35 lie at such intervals from each other that in each case one of the switchingfcams 5., 6', 7 which are represented in aishaded manner can move freely between them. The switching cams are represented in the axial and radial center position oltheswitchingsleeve.1. From this position there is .engaged by means ofthe switching camV 6 through a rotationlto/ the right. of. the switching, sleeve Y (s'ee Fig.

' 2) the second gear and by means of switching cam 7 Yby rotation to the. left ofswitching sleeve 1 the first gear. Upon actuating .one of ,the switching cams which is` inv engagement the other one remains lwithout effect because ofits .displaced arrangement..

Upon longitudinal displacement. oi switchingsleeve 1 upwardly the cam 5 comes into engagement with the switching rod 13 .and engages by a rotation to the left of switching sleeve 1 the reverse gear. Upon a longitudinai displacementv of the .switching sleeve 1y downwardly cam 7 is released. Cam 6 displacesnpona rotation to tlreu'ght the switching rod 15.10 the left (ourthgear) andk cam 5^moves',npon a rotationY .to the left, switching rod 14 to the right (third gear).

The arrangement :of .the cams and. cut-ont portions shown for the :four `forward. gears .and one. reverse gear represents only one possible embodiment. -For instance, one .can provide Vby arranging a second cut-.out section on the switching rod :13 and a fourth cam in the swing of .cam .6 a switching possibility for a furtherY gear. This further gear wouldk beswitched by :rushing the switching lever into. its end portion and hya rotation to the right. Slide plate 30 is attached .on drive housing 29 (see Fig. 1) .andvhas three cut-out portions 31 (Fig. 2) which correspond to the three longitudinal positions to switching sleeve"1.- Plate 'SZ'is connected with it and has a slot 33 (see Fig. l). Plate 32 hasV the-effect that the longitudin'all displacement of switching sleeve k1 is V.possible only '-in its neutral position, which isv drawn. Similarly the rotation is. possible only in the three switching posi- .tionsQwhich are-determined by the three cut-:out portions 31.. The two outerY fingers 34 (Fig. 2,) limit thelongitndinal movement-.of theswitching sleeve inthe neutral position.;

f .Figurev shows the three-switching rods 13, 14, 15 again in plan view. The three surface strips, 57, .58, 59 indicatedby .phantom lines show the course of a gang cutterwhichworks on the. front and back. working surfaces offledges 35er cut-out portionsfs'to 12 during the `saine clamping operation. Y Y

Figure 4 represents a cross section through the switching arrangement along line C-D (Fig. I). Numeral 1 indicates the switching sleeve with plate 32 and the switching cams 5, 6 and 7. Below the switching sleeve the three switching rods 13, 14, 15 with the individual switching ledges 35 are mounted. Switching sleeve 1 is provided with a pot 36 in which the ball-shaped end 37 of switch lever 3S reaches. Switching lever 38 is mounted movably in ball socket 39.

In eye 49 of drive housing 29 a spring biasedv ball v4,1 is mounted against which switching sleeve 1 makes contact with a stop 42 in the central vposition shown. Before moving from this central position to the right into the position for the reverse gear the resistance of the spring biased ballV 41 has to be overcome. At the .outer end of switch lever 38 the switching diagram of the individual lever positions for the first to the fourth gear and the reverse gear are indicated.

Figure wshowsfa further Vembodiment l.of an lactuating lever. `@n shatZ v:of .switching sleeve 1 anglel arm 53. is'rattachedg. The latter basa bail 43 which reaches into the cylindricalv sleevetaub-switching lever 45. Switching lever 45.1's rotatable about-lits. vshaft 46 and mounted .so asto'he .displaceahle longitudinally in its direction and can be actuated by a switching arrangement which is mounted .on .thezsteering w eel. The numerals 1- .to 4 with .the Vrletter .R V:indicate the .switchingV diagram.

.Figure v6 represents switching sleeve I'of Fig. l .in larger .-scale,.fnamely.in the neutral position infull lines, inthe position atztlie end .ofthe engaging vmovement in hatched lines. Numeral .8 indicated .the cut-out portion inthe switching rod T13. Cam 7 has a front edge 20 with the curvature radius r1 andV arhack edge 21 with the .curvature radius-.152. 'lihefront and hack yedges yhave a common' center of lcurvaturet. The force contact pointat the beginningofthe engaging movement between the rontedge .26. and the .contact making edge of cut-out portiorr .lies in .theiilever interval-h1. from .the point of rotation; :at the end of the .engaging movement however in thev larger .interval h2.v Upon an opposite rotation l from the neutral position towards the left the vcam comes oui .of .engagement while a further vcam which is not represented, havinga mirror image arrangement, is kengaged'npon. :thev same .direction of rotation toward the left. VThe ratio switch lever length: carn width is approximately 1.22.

4Figure' 7 showsa .further possible embodiment of the switching cam with Vthe same radius Yof curvature r of the lfront and backedge. Cam n47 is represented in the neutralv positionLi-ntull lines `and at the end of the engaging V.position in :hatched lines. Y

The Vworking edgewS of cut-'out portion 51 for the engagingmovementis higherthan the opposite edge 52. Furthermore. the corresponding edges of cam 47 are of diierent'length, namely the :front edge 48 is longer than the back edge 49. vIt is thus obtained that the cam is engaged VWith'theiswitching rod from the neutral position only in one-direction of rotation. 1

I claim: .Y i Y l. A gear .shift mechanism comprising a plurality of reciprocal gear shifting bars having notches, and cams selectively engageable in respective notches for shifting respective vbars,.1neans.for selectively actuating said cams by rotation thereof, each of said cams having a pair of cam surfaces-engageable withthe opposedv sides of an Aengaged notch to move a bari-in one direction or the opposite direction, said .cam surfacesgof eachcam being cir- .cularand havinga .common centerzof arcuateness, Awhereinthe cam surface for movinga barin saidzone direction isV of larger radius .than the -other cam surface, thetcenter 'ofi-rotation offsaid cam Ibeing osetV from the center of arcuateness of said cam surfaces toward the cam surface of' larger radius.

j '2..v A gear lshifting mechanism for motor vehicles comprising a plurality of slidable, spaced shifting rods paralfront and back cam edges of circular contour, said back lel to each other and provided with recesses having longiedges being of smaller radius than said front edges. tudinally spaced Walls, a rotative sleeve member longitudinally slidable in a direction normal to the parallel References Cited in the file of this patent axes of said rods and in a plane substantially equally 6 UNITED STATES PATENTS spaced from the plane of said axes, said sleeve having shifting cams engageable with the Walls of the recesses 2344096 Kummlch Mar 14 1944 of selected shifting rods, said cams being provided with 2485034 Bugatti Oct' 18 1949 

